Presently, ball valves are of the straight flow through in line type such as illustrated in U.S. Pat. Nos. 3,367,623 and 3,614,056, or of the type which forces a change in flow direction such as angle or tee ball valves. See U.S. Pat. No. 3,286,735. These constructions have been proposed for use as commodity discharge valve on tanks or railroad tank cars.
With the advent of the Association of American Railroads (AAR) protective regulations, valves located below and outside of tank cars, must now be protected against opening, or otherwise being damaged, when the tank car is involved in an accident. Protective means presently employed are heavy and costly skids or locating the valve inside the tank. See AAR Tank Car Specifications, Regulation E-10, (copy in application file).
Valves located inside the tank have economic and size restrictions imposed upon them. See U.S. Pat. Nos. 3,591,131, 3,661,355 and 3,286,735. In order to avoid costly skids, either separate or as part of the tank mounting flange, the internally located valves must be held to given size which in turn limits the discharge flow rate. Conversely, in order to optimize flow rates, conventional valves must have relatively large inlet ports in relation to the outlet port.
U.S. Pat. No. 2,579,567 discloses a valve member extending through an inclined valve housing. The valve member is movable longitudinally relative to the housing between a closed position engaging a valve seat and an open position allowing entry or exit of a heat transfer medium. However, the lading valve is located within the heat transfer medium discharge conduit and thus a skid or other protective device would be required to comply with the above AAR regulations.
A Homestead Ballcentric.RTM. valve (Brochure in application file, Homestead Valve Manufacturing Company, P.O. Box 2585, Bethlehem, Pa. 18001, (215) 868-4061), comprises a ball segment. However, the segment is shaped differently than the valve segment(s) of the present invention. Furthermore, the Ballcentric rotates 90.degree. between open and closed position and is not cammed into closed and seated position.